Swivel joint



April 1951 s. H. B. ZACHARIASSEN 2,547,106

SWIVEL JOINT Filed Feb. 4, 1948 2 Sheets-Sheet 1 I /nven/o r 5/l'g Hb/ger Q/arne Zachar/assn 9 Buds. W 4m Afforneys April 1 s. B. ZACHARIASSEN 2,547,106

SWIVEL JOINT Filed Feb. 4, 1948 2 Sheets-Sheet 2 K I36 25 m 27 /7b .23 25 22 g 5 65 m, 3 70b 17 Fig. 5

/nven/or 5/19 Ho/ger B 'arne Zachan'assn Patented Apr. 3, 1951 SWIVEL JOINT Stig H. Bjarne Zachariassen, Stockholm, Sweden, assignor to Aktiebolaget Separator, Stockholm, Sweden, a corporation of Sweden Application February 4, 1948, Serial No.

In Sweden March 3, 1947 12 Claims- (Cl. 285-97-1) This invention relates to a tightening device in centrifugal separators, intended to be used between the bowl and a stationary inlet or outlet pipe, so as to obtain a communication between these parts in which only a relatively insignificant leakage of liquid is likely to occur.

'It has previously been suggested to use a tightening device for the same purpose, having a tightening ring with a cylindrical, spherical or plane tightening surface supported by a corrugated tube and contacting with a tightening disc fixed to the rotating separator bowl. The use of corrugated tubes in constructions of this kind is, however, objectionablein some cases, because the tightening device cannot then be used for a corrosive liquid, for example sulphuric acid, as this would eat through the thin wall of the corrugated tube. There are other instances in which corrugated tubes may be unsuitable, for example, where the centrifuge inlet or outlet contains high pressures" which a corrugated tube cannot stan 1 The present invention, therefore, is directed to the provision of an improved tightening device by which the above-mentioned inconveniences are overcome. In the new device, the tightening ring, or a holder or the like connected thereto, is arranged to swing or otherwise move relative to a stationary part, and a packing ring is provided between-the tightening ring or the holder and the stationary part.

For a better understanding ofthe invention, reference may be had tothe accompanying drawings, in which Fig. 1 is a side elevational view, partly insection,-of the upper partof a separator made in-v .accordance with the invention;

Fig. 2 is a vertical sectional View of the upper part. of a modified form. of the-separator,'and Fig. 3 is a view similar to Fig. 2 but showing still another form of the separator.

In the. embodiment according to Fig. 1, which shows a separator provided "with. a liquid seal in the outlet, a stationary outlet tube I is formedin the cover I3 of. the. frame, through which outlet the centrifuged liquid is discharged. from aseparator bowl 2.. A tightening disc 3 is secured to the upper part of bowl 2 by a: nut The tightening disc 3 is engagedby a tightening ring 5 supported by a holder 6, which is guided in the outlet tube I There is .a clearance between. the periphery of'holder 6 and the outlet tube I,

this clearance being such that the l b t the outlet tube I and the holder 6 is just sufficient to permit the holder 6 to swing somewhat. According tothe lateral deviation and the angular movement of the separator bowl 2 incident to its rotation, which cause tilting of the bowl and therefore its tightening disc 3, the tightening surface of the ring 5 may thus assume such positions that it remains parallel with the tightening surface of the disc 3, with which it cooperates. Above holder 6 is a packing ring I of, for example, rubber which surrounds the-tube I and is kept pressed on the holder 6 by a disc 8 acted upon by a spiral spring 9'. The latter at the same time exerts a pressure on holder 6 great enough always to insure contact between the tightening ring 5 and the tightening disc 3, even if the tightening surfaces of these parts should become somewhat worn.

In its free condition, the inner diameter of packing ring I is somewhat smaller than the outer diameter of outlet tube I, which insures a satisfactorytight joint between the cylindrical surfaces of these parts, since the packing ring I must be expanded to force it on the outlet tube I.

In addition to the pressure exerted by spiral spring 9', which is transmitted to "tightening ring 5 via packing ring 7- and holder 6, the pressure of a sealing liquid surrounding outlet tube I' (as will be described presently) also contributes to an increased tightening effect between tighten-- ing ring 5 and tightening disc 3, since the outer diameter of outlet tube I is, smaller than the average diameter of the tightening surface of ring 5, whereby the latter ring is pressed against the tightening disc 3. With this arrangement, even with high liquid. pressures at the bowl outlet and' in spite of the movements performed by the bowl, the onlyleakage which can occur will be in the form of a thin film of liquid between the tightening ring 5 and the tightening disc 3.

A packing ringv I0 arranged ina holder II, alsocontactsthe disc 3. The ring IB and holder II surround the lower part of outlet tube! in spaced relation thereto and are connected with the cover I3 of the frame by means of a cor-v rugated tube or bellows I2. The parts thus define a space I4 to which the sealing liquid is fed through a channel I5 in the cover I 3; In the space I4 is a tube It threaded to the top of cover I3, from which it extends downwardly between the bellows I2 and the outlet tube I. At its lower end, the tube i6 is provided with an inwardly projecting fiange'or stop I? which limits the downward movement of the holder 6'.

It willbe understood that'thesealing liquid issupplied from inlet 1 5 throughthe space between bellows I2- and tube I6, around the bottom of screwed into a ring 20 .3 tube |G, through the space between holder 6 and tube I6, and into the annular chamber between the tubes and Hi.

In the embodiment illustrated in Fig. 2, the invention is applied to the outlet from a separator without sealin liquid, the pressure on the inside of the seal being higher than on its outside. In 'the top of the separator bowl 2a is screwed a holder H3 in which is located a tightemng disc 3a which thus rotates with the separator bowl, as in the Fig. l embodiment. A tightening ring 5a, supported by a holder 6a, contacts the tightening disc 3a. On its outer side, the holder 6a. is guided by the inner cylindrical surface of a sleeve l9, which in turn is |3a of the separator frame. The cylindrical guiding surface between holder 6a and sleeve threaded in the cover,

I9 is short and so formed as to allow movement of holder 6a relative to the axis of the separator.

As in the embodiment shown in Fig. 1, a packing ring 1a of rubber is provided above the holder 6a. Ring la is in this case so dimensioned that, upon bein placed in the sleeve l9, it exerts an outward expansive force against the inner cylindrical guidin surface of sleeve l9. Above packa disc 8a with which a spiral purpose of which is to 5a against tightening the embodiing ring 1a is spring 9a contacts, the press the tightening ring disc 3a in the same manner as in ment shown in Fig. 1. The packing ring 1a. is,

however, provided with conical top and bottom surfaces 2| so that, under the pressure of spring 9a, the packing ring is forced towards the clear ance between holder Ba and the cylindrical inside of sleeve l9.

In the arrangement shown in Fig. 3, the packing rin lb consists of a rubber ring of U-shaped section and is placed in a groove in the inner surface of holder 62). The packing ring lb may, however, also be made of a metal. Between holder 6b and outlet tube I there is also a packing ring 2| of L-shaped section and made of thin sheet material, the ring 2| being seated on top of the holder 6b. The fit of the cylindrical part 2| is preferably such that a good tight joint is obtained between it and the outlet tube In this construction, the outer holder II b presses the outer packing ring lub on the disc 3 by means of a spring 22. Into the cover lSb of the frame a sleeve 23 is threaded, which is provided with an inwardly projecting flange 24 with which a packing rin 25 contacts, the latter being fixed on the holder Hb. This packing ring is compressed by a ring 21, actuated by a spring 26, whereby a tight joint is obtained between the sleeve 23 and the packing ring 25 as well as between the latter and the holder lb so that the space Mb, intended for the sealing liquid, is closed without using a corrugated tube or bellows.

It will be apparent that in the illustrated forms of the invention, the centrifuged liquid from the separator bowl is discharged through the stationary tube (Figs. 1 and 3) or 19 (Fig. 2), and the passage between the bowl outlet and the stationary tube is so arranged as to prevent any substantial leakage of the outflowing liquid and yet allow the usual relative movement between the rotating and stationary parts due to vibrations and any unbalanced condition of the bowl. More particularly, the tightening member 3 can move laterally relative to the tightening ring 5 which it contacts, although this movement occurs while the parts are pressed together by the spring 9 so that there will be no appreciable leakage between the sealing surfaces. The packing ring 1 (2| in Fig. 3), which is also compressed by the spring 9, prevents leakage between the tightening rin 5 and the stationary outlet tube, and at the same time, because of its flexible nature, it allows some relative movement between the holder 6 and the stationary outlet tube. The spring 9 serves to accommodate vertical movements of the bowl relative to the frame cover l3 and also to maintain a constant pressure between the sealing surfaces of the parts 3 and 5 in spite of wearing of these parts. In the Fig. 1 and Fig. 3 embodiments, the outer tightening ring I0 is also adapted to slide on the tightening disc 3, against which it is pressed, to accommodate lateral movements of the bowl. The tightening rings In, of course, serve to retain the sealing liquid which exerts an additional pressure on the relatively movable sealing surfaces.

While the invention has been specifically described and illustrated in connection with an outlet of a centrifuge, it will be understood that it may be applied with equal facility and with the same advantages to the centrifuge inlet. Also, the construction may vary in its details, within the scope of the appended claims.

I claim:

1. In a centrifuge having a centrifugal bowl and a stationary pipe communicating with the interior of the bowl, the combination of a tightening disc rotatable with the bowl and having an opening through which communication is afford.- ed between the bowl and saidpipe, the disc moving radially and tilting with the bowl relative to the stationary pipe incident to the bowl rotation, a tightening ring engaging said disc and surrounding said opening, said disc being movable relative to the tightening ring while maintaining a sealing contact therewith, and a packing ring of rubber-like material interposed between the tightening ring and the stationary pipe, said packing ring and tightening ring at least partly defining a passage communicating'between the bowl and said pipe and acting to seal against leakage from said passage, there being a clearance between said tightening ring and the stationary pipe to allow the tightening ring to undergo axial and tilting movements relative to said pipe, whereby said tightening ring is adapted to assume relative to said disc at all times a position for maintaining a tight joint therewith.

2. A combination according to claim 1, comprising also a spring acting upon the packing ing to press the same against the stationary pipe and also to press the tightening ring against said disc.

3. A combination according to claim 1, in which the packing ring in its unassembled condition is of different size than said stationary pipe which it engages, whereby the packing ring exerts a pressure against said pipe to form a tight joint therewith by the elasticity of the packing ring.

4. A combination according to claim 1, in which the packing ring is U-shaped in cross-section.

5. A combination according to claim 1 in which the packin ring is L-shaped in cross-section.

6. A combination according to claim 1, comprising also a holder for the tightening ring and interposed between the tightening ring and said. packing ring.

7. A combination according to claim 1, comprising also a second tightening. rin engagin 5 the tightening disc and surrounding the first tightening ring, and means forming a movable joint between said second tightening ring and said pipe and partly defining a space for a seallllg liquid outside said passage.

8. A combination according to claim 1, com prising also a second tightening ring engaging the tightening disc and surrounding the first tightening ring, and a bellows forming a movable joint between said second tightening ring and said pipe and partly defining a space for a sealing liquid outside said passage.

9. A combination according to claim 1, comprising also a second tightening ring engaging the tightening disc and surrounding the first tightening ring, and means including a second packing ring of rubber-1ike material forming a movable joint between said second tightening ring and said pipe and partly defining a space for a sealing liquid outside said passage.

10. A combination according to claim 1, in which said packing ring is stretched over the stationary pipe.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,075,769 McCormack Mar. 30, 1937 2,384,281 Carter Sept. 4, 1945 

